Recently, with digital magnetic recording devices such as a tape recorder, it has become necessary to arrange a plurality of magnetic heads at a fixed distance to cope with diversified requirements. Also, it has become important to set a relative positional relationship between each of the magnetic heads and the tape guide with a high degree of precision.
By the way, among the known conditions for concrete positional relationship between a magnetic head and a tape guide are, as shown in FIG. 6 (a), the height h, h'of track patterns 2a, 3a from and the inclination .theta..sub.a1, .theta..sub.a2 of the track patterns 2a, 3a against the reference planes 1a, 1a . . of tape guide members 1, 1 . . . , the extent of protrusion .alpha..sub.1, .alpha..sub.2 of magnetic heads 2, 3 from tape guide poles 1b and 1b . . . and the distance L between magnetic heads 2, 3 shown in FIG. 6 (b) and, further, such factors as tilt and mechanical adjustment, although these are not shown in the figure. Thus, there are quite a number of conditions to be satisfied and since high precision is required with regard to each condition, it was hitherto accepted to be difficult to preassemble the tape guide and then fix the magnetic head 2 and 3 to the tape guide.
It has, therefore, been a usual practice in assembling a magnetic recording and reproducing head unit to data, as shown in FIG. 7, to adjust the mutual positional relationship between individual tape guide members 5-7 and individual magnetic heads 8 and 9 on a bottom plate 4 of the tape guide by the use of mechanical stages 10, 11 for positioning thereof along the X and Y axes and another mechanical stage 12 for azimuth adjustment and, after fixing thereof using an adhesive, to set a top plate (not shown) in place.
With regard to the magnetic recording and reproducing head unit shown in FIG. 7, however, there was a problem of an extremely long time required for assembling the tape guide and the magnetic head after adjustment of the positional relation therebetween. This delay results in a lowered productivity.
As seen from FIG. 8, therefore, the present inventor contrived an arrangement in which a housing case 51 having a magnetic head 50 housed and fixed therein is positioned and fixed in a hole 53 provided in a position adjusting portion 52 of the tape guide, and for this a patent application has already been made in Japan (Application No. 59657, '87), published as an unexamined patent application No. (Tokukaisho) as 63-225911.
In this arrangement a curved leaf spring 54 for urging the housing case 51 is positioned between the housing case 51 and the bottom of the hole 53, and the position adjusting portion 52 has a tapped hole near the top thereof for a height-adjusting screw 55 for adjusting the height of a magnetic head 50 in contact with the top of the housing case 51.
On one side of the housing case 51, a convex portion 56 is in contact with the bore of the hole 53, and the position adjusting portion 52 has an adjusting screw 57 set therethrough for pushing the other side of the housing case 51 near the top thereof and another adjusting screw 60 for pushing the aforesaid side near the bottom thereof. Through a springy piece 58 and through adjustment by these screws 57 and 60, the housing case 51 can be pivoted with the convex portion 56 as a fulcrum for proper adjustment of the inclination angle of the magnetic head 50. Opposite to the adjusting screw 57 with respect to the housing case 51, a fixing screw 61 is provided through the position adjusting portion 52 for tentatively fixing the housing case 51 to the position adjusting portion 52.
In the construction illustrated in FIG. 8, however, the height of the magnetic head 50 is arranged to be determined as the housing case 51 is pressed against the height adjusting screw 55 by the urging force of the leaf spring 54. Hence, the inclination angle of the magnetic head 50 is changed as the adjustment of the height of the magnetic head 50. Therefore, sufficient precision is difficult to attain with regard to adjustment of both height and inclination of the magnetic head 50. Another problem was the inevitable complication of the construction as the position adjusting portion 52 had to be provided with such adjusting and fixing means as the adjusting screws 57 and 60 and the fixing screw 61 et cetera.